System And Method For Underwater Oil And Gas Separator

ABSTRACT

A passive hydrocarbon containment system for containing hydrocarbons in a fluid comprises a subsea separator dome, an oil pathway in fluid communication with a hydrocarbon collector disposed within the collection dome, and a gas outlet pipe having a discharge height dimensioned and adapted in relation to the height of the oil pathway sufficient to keep a portion of the oil pathway submerged into a fluid such as seawater present in the collection dome interior void. The hydrocarbon containment system can be moored subsea and used to collect oil and gas coming out of the ocean floor. One advantage of the hydrocarbon containment system is that there are no moving parts. A further advantage is that the hydrocarbon containment system requires limited maintenance to pump out the collected oil as needed.

RELATION TO OTHER APPLICATIONS

This application relates to and claims priority from U.S. ProvisionalApplication 61/088,182.

FIELD OF THE INVENTION

Recovery of oil and/or gas subsea, especially from hurricane downedstructures with leaking production wells. In its preferred embodiment,the separator works best with an oil and gas leak. Although currentlycontemplated embodiments also work with oil-only leaks, such wouldtypically require an almost vertical placement to the domes used tocapture the leaking production.

BACKGROUND OF THE INVENTION

Downed platform and submerged hydrocarbon conduits can become victim touncontrolled oil and gas leaks. For example, platforms toppled byhurricanes can have multiple wells leaking oil and gas, creating an oilsheen on the surface and polluting exposed shorelines. Current oil andgas separation is performed on the water's surface using support vesselswith separator equipment, or skimmer vessels, and/or cleaning crews toremove leaked oil from beaches. Surface vessels typically haveseparation units and recover the oil from the surface once it creates asufficient sheen. Typically, a flare tower is not needed as the depthfrom which the gas is venting does not allow visible gas bubbles to showon the surface.

Collection domes can be used to effectively collect the leaking oil andgas streams, but, as the water depth (e.g., over 100 fsw) and distancefrom other fixed structures increase, the ability to separate thecollected oil and gas from the leaking wells becomes a challengerequiring a topside support vessel. Further, subsea installation avoidstopside support vessels which may or may not be able to stay on locationin bad weather.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view in partial cutaway perspective of a currentlyenvisioned embodiment;

FIG. 2 is a view in further partial perspective of a top portion of acurrently envisioned embodiment; and

FIG. 3 is a view in further partial perspective of an exemplarydeployment.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring now to FIG. 1, hydrocarbon containment system 10 can be mooredsubsea and used to collect oil and gas coming out of the ocean floor.Hydrocarbon containment system 10 comprises collection hydrocarbonstorage area 26; hydrocarbon separator upper portion 30 disposed inupper portion of separator interior void 21; oil pathway 40 in fluidcommunication with hydrocarbon collector 30, oil pathway 40 disposedwithin collection separator interior void 21 and having a predeterminedheight; one or more oil drainage pathway 42; and gas outlet pipe 50having a discharge height dimensioned and adapted in relation to theheight of oil drainage pathway 42 sufficient to keep a portion of oildrainage pathway 42 submerged into fluid 100 present in separatorstorage interior void 26.

Separator lower area 20 comprises interior void 22, substantially closedupper end 23, and substantially open lower end 26

In certain embodiments, separator area 30 further comprises one or morebaffles 32 which comprise one or more baffle plates 33. Baffle 32 may beangled at a predetermined angle. In an embodiment, baffle 32, e.g. itsbaffle plates 33, are angled. In other embodiments, a surface area maybe added, e.g. in between baffle 32 and inlet areas 40, to give anadditional surface to which oil may adhere.

Referring additionally to FIG. 3, hydrocarbon containment system 10 mayfurther comprise buoyancy collar 28 integrated into and/or attached toseparator 10 and used to control depth of separator 10 in the watercolumn. Ocean floor mounted units would typically not need buoyancycollar 28 which may be used raise hydrocarbon containment system 10 toallow proper upward flow such as using hoses 39 from collection domes110.

One advantage of hydrocarbon containment system 10 is that there are nomoving parts. A further advantage is that hydrocarbon containment system10 requires limited maintenance to pump out the collected oil as needed.

In the operation of a preferred embodiment, referring to FIG. 1 andgenerally to FIG. 3, hydrocarbon containment system 10 is used as asubsea oil and gas separator which can be installed underwater tocollect oil and gas, e.g. from downed platforms, natural seepage anddamaged pipelines. The collected oil and/or gas can be collected, e.g.in collection domes 110, and directed into hydrocarbon containmentsystem 10 such as using hoses 39. In an embodiment, hydrocarboncontainment system 10 removes the oil from the gas, contains the oil,and vents the gas.

Once inside separator area 20, the oil will be separated and gravitatedown into separator area 20 while the gas may be vented back into thesea water by vent pipe 50.

Multiple hydrocarbons discharges may be contained underwater by locatinga source of leaking hydrocarbons, typically a broken pipeline orwellhead device; collecting the leaking hydrocarbons using one or morecollection domes 10; and piping the collected hydrocarbons tohydrocarbon containment system 10 with hoses 39 using a fluid such asseawater. Hose 39 typically mates with separator inlet pipe 40, allowingthe hydrocarbons to enter into hydrocarbon containment system 10 throughseparator inlet pipe 40.

The hydrocarbons in fluid 100 condense onto a collector such as baffle32 and drain down hydrocarbon drains 42 and the non-gas component of thehydrocarbons flow out gas vent 50. For example, ambient seawaterprovides balancing pressures for hydrocarbon containment system 10,using the gas coming into separator area 20 to create the flow andmaintain the gas envelope required in collection dome 20 so that gravitycan help collect the oil, separate the oil and gas by flow throughbaffles 32, and let the collected material flow down into separatorstorage area 26 by passing down drains 42. Accordingly, storedhydrocarbon fluid 100 is allowed to partially enter into separatorinterior void 22 above lower ends of drains 42 such that a portion ofdrains 42 is submerged into stored hydrocarbon fluid 100 in separatorinterior void 22.

Gas outlet port 50, which is in fluid communication on the dischargeside with the ambient sea water or other fluid and located proximatesubstantially closed upper end 23, and gas outlet port 50 disposedoutside separator 20 may be present, as in the preferred embodiment. Inthis embodiment, the gas component present in separator interior void 22exits separator interior void 21 through gas outlet port 50 and isvented to ambient sea water or fluid through gas outlet port 50. Thedischarge end of gas outlet port 50 is positioned at a height relativeto separator void 20 sufficient to control the level of fluid 100 withincollection dome 20. Moreover, gas outlet pipe 50 may be dimensioned suchthat its discharge height, in relation to the length of drain 42, issufficient to keep a portion of drain 42 submerged into fluid 100present in separator interior void 22.

Hydrocarbon containment system 10 may be positioned using gravity, aremotely operated vehicle (ROV) (not shown in the figures), or the like,or a combination thereof Additionally, buoyancy collar 28 (FIG. 3) maybe integrated into and/or attached to collection dome 20 and used tocontrol a depth of collection dome 20 in fluid. By way of example andnot limitation, separator 10 may be moored, e.g. to an underwater devicesuch as a wellhead or pipeline, to achieve a predetermined locationrelative to the source of hydrocarbons in fluid. Such mooring may besecured to allowing hydrocarbon containment system 10 to use buoyancy,either a natural buoyancy or buoyancy created or augmented by buoyancycollar 28, to float mid-water, by anchoring separator 10 to a suctionpile, by attaching separator 10 to a fixed subsea structure, or thelike, or a combination thereof. Surface buoy 120 may be tethered tohydrocarbon containment system 10 such as by connector 38 and terminus25 (FIG. 2).

Strategically placing the gas outlet 50 discharge height in relation tothe height of drain 42 keeps the drain outlets under the fluid levels100 and prevents gas flow bypassing the flow path through baffles 32.The whole separation process is completed without any moving parts.

The foregoing disclosure and description of the inventions areillustrative and explanatory. Various changes in the size, shape, andmaterials, as well as in the details of the illustrative constructionand/or a illustrative method may be made without departing from thespirit of the invention.

1. A hydrocarbon containment system, comprising: a. a subsea separatorcomprising an interior void, a substantially closed upper end, and asubstantially open lower end; b. a hydrocarbon separator disposed in anupper portion of the subsea separator interior void; c. an oil pathwayin fluid communication with the hydrocarbon separator storage area, theoil pathway disposed within the separator dome interior void and havinga height; and d. a gas outlet pipe having a discharge height dimensionedand adapted in relation to the height of the oil pathway sufficient tokeep a portion of the oil pathway submerged into the fluid present inthe collection dome interior void.
 2. The hydrocarbon containment systemof claim 1, wherein the separator further comprises a baffle.
 3. Thehydrocarbon subsea separator system of claim 2, wherein the bafflecomprises a baffle plate.
 4. The hydrocarbon subsea separator system ofclaim 2, wherein the baffle is angled at a predetermined angle.
 5. Thehydrocarbon subsea separator system of claim 1, wherein the oil pathwaycomprises a standpipe.
 6. The hydrocarbon subsea separator system ofclaim 1, further comprising a buoyancy collar attached to the separatordome.
 7. The hydrocarbon subsea separator system of claim 6, wherein thebuoyancy collar is integrated into separator dome.
 8. A method ofcontaining hydrocarbons underwater, comprising: a. locating a source ofhydrocarbons in a fluid, the hydrocarbons comprising a gas component anda non-gas component; b. positioning a hydrocarbon containment systemproximate the source sufficient to allow the hydrocarbons to enter intothe containment system, the containment system comprising: i. aseparator dome comprising an interior void, a substantially closed upperend, and a substantially open lower end; ii. a separator disposed in anupper portion of the separator dome interior void; and iii. an oilpathway in fluid communication with the separator, the oil pathwaydisposed within the separator dome interior void and dimensioned andadapted to extend a predetermined distance towards the collection domelower end; c. allowing the fluid to enter into the separator domeinterior void through the lower end such that a portion of the oilpathway is submerged into the fluid in the collection dome interiorvoid; d. allowing the hydrocarbons in the fluid to condense onto thecollector; e. allowing the non-gas component of the hydrocarbons tocollect on the oil pathway; f. allowing gravity to return the non-gascomponent of the hydrocarbons to the fluid in the separator domeinterior storage area.
 9. The method of containing hydrocarbonsunderwater of claim 8, further comprising: a. providing a gas outletpipe, the gas outlet pipe comprising (i) a gas inlet port in fluidcommunication with the separator dome interior void and disposedproximate the substantially closed upper end and (ii) an gas outlet portdisposed outside the separator dome; and b. allowing the gas componentpresent in the upper portion of the separator dome interior void to exitthe separator dome interior void through the gas outlet port.
 10. Themethod of claim 9, further comprising positioning the gas outlet port ata height relative to the separator dome sufficient to control the levelof fluid within the separator dome.
 11. The method of claim 9, whereinthe gas outlet pipe discharge height is dimensioned in relation to theheight of the oil pathway sufficient to keep a portion of the oilpathway submerged into the fluid present in the collection dome interiorvoid.
 12. The method of claim 8, wherein the fluid is seawater.
 13. Themethod of claim 8, further comprising: a. attaching a buoyancy collar tothe collection dome; and b. using the buoyancy collar to control a depthof the collection dome in the fluid.
 14. The method of claim 8, furthercomprising mooring the collection dome to achieve a predeterminedlocation relative to the source of hydrocarbons in a fluid.
 15. Themethod of claim 14, wherein the mooring is at least one of floatingmid-water, anchoring the collection dome to a suction pile, or attachingthe collection dome to fixed subsea structure.